1. Field of the Invention
This invention relates to a sheet-bundle conveying device, and more particularly, to a bound-bundle conveying device for binding a bundle of sheets and conveying the bound bundle, and to a binding apparatus including the device.
2. Description of the Related Art
In the related art, as shown in FIG. 20, a binding apparatus 1 includes a sheet conveying device 201, a sheet aligning device 202, a sheet-bundle conveying device 203, a tape heating device 204, a tape conveying device 205, and an accommodating stacker 207.
The sheet conveying device 201 has a sheet conveying path 2 for a received sheet S. A receiving port 2a and a discharging port 2b are provided in the sheet conveying path 2, and a pair of receiving rollers 3, a plurality of pairs of conveying rollers 4, and a pair of discharging rollers 5 are disposed from the upstream side along the sheet conveying path 2. A flapper 6, serving as branch means, is disposed at the downstream side in the vicinity of the pair of receiving rollers 3. The flapper 6 causes the sheet conveying path 2 to branch to a sheet conveying path 7 when performing binding.
The sheet S branching to the sheet conveying path 7 by the flapper 6 is conveyed to the sheet aligning device 202 by a pair of sheet conveying rollers 8 comprising components 8a and 8b.
The sheet aligning device 202 comprises an accommodating tray 9 for accommodating sheets, an aligning fence 10 for aligning the sides of the sheets parallel to the sheet conveying direction, an aligning paddle 11 for aligning the sides of the leading edges of the sheets in the sheet conveying direction, a stop finger 12 for temporarily holding the sheets at each binding operation, a leading-edge reference shutter 13 with which the leading edges of the sheets are brought into contact, a lower entrance guide 14 for guiding the lower surface of each sheet at an entrance of the device, and an upper entrance guide 15 for guiding the upper surface of the sheet at the entrance of the device.
The sheet S received in the sheet aligning device 202 contacts the leading-edge reference shutter 13 while the upper surface and the lower surface of the sheet S are guided by the upper entrance guide 15 and the lower entrance guide 14, respectively. At that time, alignment of the sheet S in the sheet conveying direction and alignment of sides of the sheet S parallel with the sheet conveying direction are performed by the aligning paddle 11 and the aligning fence 10, respectively, on the accommodating tray 9.
The sheet-bundle conveying device 203 comprises a movable grip plate 17, a fixed grip plate 16, a sheet-bundle guide 18 and the like.
Upon completion of alignment of sheets by the sheet aligning device 202, a grasping driving mechanism (not shown) for the movable grip plate 17 operates to move the movable grip plate 17 in order to grasp the bundle of the aligned sheets together with the fixed grip plate 16. Upon completion of grasping of the sheet bundle, a moving mechanism (not shown) for the movable grip plate 17 and the fixed grip plate 16 operate to convey the aligned sheet bundle from the sheet aligning device 202 to the tape heating device 204 in the state of the sheet bundle being grasped.
At that time, the lower side of the rear end of the sheet bundle is guided and supported by the sheet-bundle guide 18.
The sheet-bundle guide 18 also moves together with the movable grip plate 17 and the fixed grip plate 16.
The tape heating device 204 comprises tape guides 19 and 20, a central heater 21, side heaters 22 and 23, a driving mechanism 24 for the central heater 21, a driving mechanism 25 for the side heaters 22 and 23, and the like.
A binding tape 26 is supplied to the tape guides 19 and 20 of the tape heating device 204 by the tape conveying device 205 before the aligned sheet bundle is conveyed by the sheet-bundle conveying device 203.
The tape conveying device 205 comprises tape reels R1 and R2, a carriage conveyor C, a tape cutter 42, tape conveying means 43 and the like.
A tape wound around the tape reels R1 and R2 is cut into a predetermined length by the tape cutter 42 to provide the binding tape 26, which is conveyed into the carriage conveyor C by the tape conveying means 43.
When the binding tape 26 has been conveyed into the carriage conveyor C by the tape conveying means 43, the central heater 21 moves from a retracted position (not shown) to a heating position by the driving mechanism 24 for the central heater 21 and starts preheating of the binding tape 26. When the aligned sheet bundle has been conveyed to a back contact position H by the sheet-bundle conveying device 203, the back side of the sheet bundle is bound.
The bound sheet bundle is accommodated within the accommodating stacker 207 by being gripped by a gripper comprising the movable grip plate 17 and the fixed grip plate 16.
Thus, the sheet bundle moves from the aligning device 202 to the tape heating device 204 (serving as a binding unit) and then to the accommodating stacker 207 (serving as an accommodating unit) by being gripped by the gripper.
In the above-described related art approach separate rails and driving systems are provided for six operations, i.e., a (grasping), b (movement), c (movement), d (rotation), e (movement) and f (movement between the front side and the rear side), and many of the driving systems are included within moving members, thereby providing a complicated and high-cost configuration.
In the conventional approach, if the operations d and e are omitted, a bound bundle drops when being accommodated. Hence, a shock is produced by the impact on the bound bundle, and disturbance is generated in the bound bundle.
In the related art approach, since the gripper for holding the sheet bundle is moved by the driving system having degrees of freedom in six directions, the following disadvantages are present. That is, (1) a large amount of cost is required for the driving system for the gripper, and (2) the size of the device increases.